全文获取类型
收费全文 | 2686篇 |
免费 | 250篇 |
国内免费 | 791篇 |
专业分类
安全科学 | 301篇 |
废物处理 | 144篇 |
环保管理 | 219篇 |
综合类 | 1574篇 |
基础理论 | 404篇 |
污染及防治 | 666篇 |
评价与监测 | 136篇 |
社会与环境 | 131篇 |
灾害及防治 | 152篇 |
出版年
2024年 | 8篇 |
2023年 | 49篇 |
2022年 | 160篇 |
2021年 | 166篇 |
2020年 | 186篇 |
2019年 | 105篇 |
2018年 | 117篇 |
2017年 | 136篇 |
2016年 | 129篇 |
2015年 | 191篇 |
2014年 | 188篇 |
2013年 | 294篇 |
2012年 | 255篇 |
2011年 | 270篇 |
2010年 | 214篇 |
2009年 | 159篇 |
2008年 | 187篇 |
2007年 | 153篇 |
2006年 | 123篇 |
2005年 | 115篇 |
2004年 | 80篇 |
2003年 | 70篇 |
2002年 | 59篇 |
2001年 | 41篇 |
2000年 | 48篇 |
1999年 | 45篇 |
1998年 | 44篇 |
1997年 | 27篇 |
1996年 | 15篇 |
1995年 | 27篇 |
1994年 | 18篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3727条查询结果,搜索用时 15 毫秒
851.
852.
利用了2007年-2012年山西省11个城市的空气质量日报资料对空气质量的变化特征及其影响因素进行了研究分析。结果表明,太原市API指数累年平均值最大,长治市和忻州市最小;就年际变化而言,6年来,太原市API指数呈逐年下降趋势,其他城市在2011年-2012年均有不同程度的回升。空气质量的季节变化特征为夏季较好,冬季较差;各城市的首要污染物均为可吸入颗粒物。以山西省大气污染防治重点控制区太原市为例,探讨了空气质量的可能影响因素。 相似文献
853.
低温低湿条件下污泥干燥动力学特性研究 总被引:2,自引:0,他引:2
为了研究污泥在低温低湿条件下的干燥规律,获得表征水分迁移过程的有效水分扩散系数(D_(eff))和活化能(E_a),以脱水污泥为研究对象进行了污泥低温低湿干燥试验,探讨了温度(30℃、35℃、40℃、45℃、50℃)和相对湿度(20%、40%、60%)对污泥水分比(MR)和干燥速率(DR)的影响。结果表明,污泥的低温低湿干燥过程属于内部迁移控制,即水分扩散速率决定干燥速率。根据试验数据建立了污泥水分迁移动力学模型,并与6种常用薄层干燥模型进行拟合,通过对决定系数(R~2)、方差(χ~2)和残差平方和(RSS)的比较,得出污泥低温低湿干燥过程可以用Page模型来描述。结合Fick第二定律,得到不同温度(30~50℃)、湿度(20%~60%)条件下污泥有效水分扩散系数的范围为(0.699~1.991)×10~(-9)m~2/s;对传统的Arrhenius公式进行湿度修正,获得了干燥介质温度和湿度对污泥干燥特性影响的数学模型及活化能E_a=23.83 k J/mol。 相似文献
854.
855.
Yi H. Liu Jian Chen Chun M. Wang Yi R. Guo Xiao Liang Guo N. Zhu 《Journal of environmental science and health. Part. B》2013,48(6):540-546
A new method for specific antibody production was developed using antibody (Ab)-pesticide complex as a unique immunogen. Parathion (PA) was the targeted pesticide, and rabbit polyclonal antibody (Pab) and mouse monoclonal antibody (Mab) were used as carrier proteins. The Ab-PA complexes were generated by conjugating the two antibodies with an excessive dosage of PA. It was shown that the sensitivity of homologous enzyme-linked immunosorbent assay (ELISA) using the new antibodies was similar to that using original antibodies. However, the new mouse Pab had not only similar positive recognizing spectrum as the original Mab, but also a significantly improved sensitivity in heterologous ELISA when some recognizable competitors were applied. IC50 value of ELISA based on a combination of the new mouse Pab and hapten 9 was 0.24 ng/mL, which was 445.54 times as that of the homologous ELISA. An Ab-pesticide complex may be a suitable alternative immunogen for producing highly specific antibody to improve the immunoassay sensitivity. 相似文献
856.
梁高勇 《中国个体防护装备》2013,(4):9-11
在极端寒冷条件下,足部防寒保暖是一个永恒的古老话题。本文根据气凝胶具有的多级网格纳米微孔结构,介绍了二氧化硅(SiO2)气凝胶表现出不同一般的独特性能,探讨了气凝胶在军用防寒鞋袜上应用的可能性,包括保温、隔热和吸附异味等方面。 相似文献
857.
ABSTRACTThis study used hydroponics with different copper (Cu) concentrations to assess metal accumulation and growth in two different populations of Leersia hexandra Swartz, one obtained from a contaminated area (CP) and the other from a non-contaminated area (NCP). Data demonstrated that Cu exerted a lesser effect on the biomass of CP than NCP. The root and shoot biomass measurements of CP were significantly higher than those noted at NCP. Copper concentration in the tissues of L. hexandra from CP increased markedly correlated with the concentration of metal in the culture solution, and this trend was stronger than that in NCP. Copper concentrations in roots and shoots were significantly higher in CP than NCP. As Cu stress levels in the culture solution rose, the transport coefficient of both populations decreased. Furthermore, the coefficient of CP was significantly higher than NCP. At a Cu concentration of 38.4 mg/L, the transfer factor value of CP is 40% higher than NCP. In summary, CP showed higher accumulation and resistance to Cu compared with NCP. 相似文献
858.
近年来,我国各级安全生产监管部门全面落实科学发展观,坚持安全发展的理念,认真履行安全生产综合监管职能,积极探索开展综合监管工作的措施、途径和手段,逐步构筑了“分类指导、职责明晰、条块结合、运行有序、机制完善”的安全生产综合监管机制和总体格局,全国安全生产综合监管建设取得了长足的进步。但是,在综合监管工作实践中,很多地区也都遇到并提出了同样的问题:《安全生产法》等法律法规中并没有对综合监管的内容作出明确的规定。 相似文献
859.
Cong Li Jian Zhang Shuang Liang Huu Hao Ngo Wenshan Guo Yingying Zhang Yina Zou 《Environmental science and pollution research international》2013,20(8):5353-5360
Despite the many benefits of denitrifying phosphorus removal process, the significant generation of nitrous oxide (N2O), a potent greenhouse gas, remains a problem for this innovative and promising process. To better understand and more effectively control N2O generation in denitrifying phosphorus removal process, batch experiments were carried out to investigate the main causes of N2O generation, based on which the control measures were subsequently proposed. The results showed that N2O generation accounted for 0.41 % of the total nitrogen removal in denitrifying phosphorus removal process, whereas, in contrast, almost no N2O was generated in conventional denitrification process. It was further demonstrated that the weak competition of N2O reductase for electrons and the high nitrite accumulation were the two main causes for N2O generation, evidenced by N2O production and reduction rates under different conditions. Accordingly, the reduction of N2O generation was successfully achieved via two control measures: (1) the use of continuous nitrate addition reducing N2O generation by around 91.4 % and (2) the use of propionate as the carbon source reducing N2O generation by around 69.8 %. 相似文献
860.
Carrousel氧化沟的三维流场模拟与分析 总被引:1,自引:0,他引:1
利用CFD的Fluent软件,采用标准的三维K—ε紊流模型,对桂林市七里店污水处理厂1#氧化沟的流场进行了数值模拟,对导流墙和推进器附近的流速进行了计算分析。结果表明,氧化沟下层流速较低,局部区域流速低于0.2m/s。为了防止污泥沉降,应进一步降低推进器位置。能量损失分析表明,卡罗塞氧化沟能量损失主要来源于沿程摩擦损失和局部损失。可通过增加墙体光滑度、降低入口高度以及增加导流墙的曲率半径等措施减少能量损失,改善现有氧化沟的水力特征。 相似文献